We store a few PB of data in Cassandra, have used it for nearly 10 years and in my opinion it's not that hard. Operationally it's way easier to manage than Elas

We store a few PB of data in Cassandra, have used it for nearly 10 years and in my opinion it's not that hard. Operationally it's way easier to manage than Elastic and most other databases (ex. PostgreSQL, MongoDB) plus there's a ton of documentation available to help you debug/ benchmark your cluster. Note that even though CQL looks similar to SQL it's important to understand the differences but as with any new technology there's a learning curve. I would strongly recommend checking out C* if you need a database with high write throughput and that needs to scale out.